#define _CRT_SECURE_NO_WARNINGS

#include <stdio.h>

int fact(int x)
{
	int i;
	int mut = 1;
	for (i = 1; i <= x; i++)
	{
		mut = mut * i;
	}
	return mut;
}

int main()
{
	int m, k;
	scanf("%d %d", &m, &k);
	int p;
	p = fact(m) / (fact(k) * fact(m - k));
	printf("%d", p);
	return 0;
}